Our objectives are to quantify human gastric tone and gastric outlet resistance, and to elucidate their regulatory mechanisms. These objectives could not be accomplished by application of conventional methods. Thus, the proposed research starts from a base of innovative technology, developed and validated in the PI's laboratory: a barostat for quantifying gastric tone and a resistometer for quantifying antropyloroduodenal resistance to flow. This technology has been extensively validated and applied in dogs, and also tested in preliminary studies in man. Part 1 describes the instruments to be used in this research. Part 2 deals with sophisticated measurements of gastric tone in man with emphasis on regulation (response to distension, intestinal nutrients, viscerovisceral and somatovisceral reflexes). Part 3 deals with quantification of antropyloroduodenal (gastric outlet) resistance and its regulation. Part 4 brings together the preceding projects and addresses important pathophysiological issues. Specifically we will investigate abnormalities in gastric tone and outlet resistance in patients with functional disorders and the relationship of these abnormalities to the already characterized disturbances in phasic contractile activity and gastric emptying. The importance of this proposal lies on the key physiological questions it will answer by novel methodology, on the direct applicability of the information obtained to functional gut disease, and on the long-term yield of our research approach that adds a new dimension to the study of human gastric motility.